Package backing



FIG. 1 is a top view of a package Backing showing my new design, with the bottom being the mirror image thereof;

FIG. 2 is a left side view thereof, the right side view thereof being the mirror image thereof;

FIG. 3 is a front view thereof; and,

FIG. 4 is a rear view thereof.

The broken lines showing is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a package backing, as shown and described. 